Spark plug



Oct. 21, 1952 R. J. L. DUTTERER Erm. 2,614,548

SPARK PLUG Filed Aug. l. 1949 /76/5 Q/h g `spark' plugs.

Patented Oct. 21, 1952 UNITED STATES PATENT oFFlcE SPARK PLUG Rex J. L.Dutterer, Stephen I. Johnson, and Anthony J. Hein, Hastings, Mich.,vassignors to Hastings Manufacturing Company, Hastings, Mich., acorporation of Michigan Application August 1, 1949, Serial No. 107,87 6l 11 Claims. 1

The main objects of this inventionv are: First, to provide a spark plugwhich maintains its efficiency over a long period of time and at thesame -time one which can be very economically produced.

Second, to provide a spark plug which is well adapted for so-calledheavy duty use and use under severe working conditions and one in whichthe electrodes are effectively protected against erosion and againstaccidental injury in handling,

and at the same time one in which the electrodes `may be easily andeffectively "gapped or adjusted.

Third, to provide a spark plug in which the ground electrodes are soarranged and mounted that the likelihood of becoming excessively orinjuriously heated is minimized.

Fourth, to provide a method of producing electrodes having theseadvantages which results in the very rapid and economical production ofthe spark plugs with great uniformity.

Objects relating to details and economies 'of f the invention willappear from the description to follow. The invention is defined andpointed out in the claims. l

A preferred embodiment of the invention is illustrated in theaccompanying drawing. in

which:

Fig. l is a fragmentary elevational view of a spark plug embodying ourinvention, portionsv being broken away and shown in section, the sparkplug being illustrated as mounted on a combustion chamber which isconventionally illustrated. ,I

Fig. 2 is an enlarged inner end view partially sectioned and brokenaway, an adjusting tool for an'electrode being shown in section inoperative relation thereto.

Fig. 3 is an enlarged fragmentary view in section on a linecorresponding to line 3--3 of Fig. 4.

Fig. 4 is an enlarged fragmentaryV view illus- In the accompanyingdrawing, i representsa 'y wall of an internal combustion engine having athreaded bore 2 therein. The embodiment of our spark plug-illustratedcomprises a metallic shell 3 having external threads 4 at its inner endadapted to threadingly engage the threaded bore 2 in the wall l. Theinsulator 5, desirably a ceramic insulator, is mounted in the shell, thedetails of the mounting and sealing of the shell forming no part of thisinvention but may be conventional.

The'inner end of the insulator projects centrally within the inner endof the shell and terminates in spaced relation to the inner end thereof.The insulated electrode 6 is suitably mounted in the insulator toproject centrally of the shell and preferably terminating adjacent or inthe plane of the inner end of the shell but not extending beyond the endof the shell. Two ground electrodes 'i are provided in the embodimentillustrated. To mount these electrodes on the shell in such manner thatthey are fully protected by` the shell and in effective heat transferrelation thereto, we form in the shell opposed pairs of slots B whichare tapered upwardly and have rib-like raised portions 9 in thebottomsthereof. The corresponding slots of the pairs, are arranged inalignment as is clearly shown in Fig. 2, the planes of the aligned slotsbeing on opposite sides of the insulated electrode 6. The electrodes 'lare preferably formed of rod stock having parallel sides l0, as shown inFig. 4, and rounded edges Il. These electrodes are arranged in the slotsas shown in Fig. 4 and subjected to pressure and resistance weldingcurrent with the result that they are expanded into the `slots 8, asshown in Fig. 3, and welded to the walls thereof as indicated at l2.

The Ywelds are not shown in this figure as extending to the edge of theshell but that depends on the length of time the parts are subjected tothe welding current. The weld should be such that an electrode isexpanded into the slot into heat transfer connectionwith the wallsthereof and desirably welded thereto throughout a substantial portion ofthe contacting surface as is ment they may be readily formed by amilling cutter.

The slots which do not receive the electrodes serve a double purpose,one being that they provide a support for a tool such as is indicated atI3 to facilitate the proper spacing of the ground electrodes from theinsulated electrodeI and the other is that their edges form reamingedges for clearing the threads of the plug receiving bore of thecombustion chamber. It is common experience that when a spark plug isremoved the threads are more or less fouled with carbon or other depositwhich must be cleaned out before a new spark plug can be properlyseated. Spark plugs embodying our invention are highly eincient and verydurable. We are aware that the art discloses spark plugs in which theground electrodes are shrouded but we are not aware of spark plugshaving ground electrodes mounted as in our invention or having theadvantages of our structure.

We have illustrated and described a practical commercial embodiment ofour invention and have not attempted to illustrate or describe otherembodiments or adaptations as we believe this disclosure will enablethose skilled in the art to embody or adapt our invention as may bedesired.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent is:

1. A spark plug including an insulator and an insulated electrodecarried thereby and projecting centrally from its inner end, a tubularmetallic shell for said insulator, the insulated electrode beingsupported centrally of and terminating within the shell, said shellhaving opposed pairs of aligned slots extending axially from andvopening at i-ts inner end edge, the planes of the pairs of slots beingon opposite sides of the insulated electrode and laterally spacedtherefrom, and ground electrodes disposed in diagonally 'opposite slotsand with their inner ends within the shell and spaced from the alignedslots and in side overlapping relation to 'the insulated electrode andlaterally spaced therefrom, said ground electrodes being within theshell and guarded thereby and adjustable toward or from said insulatedelectrode, the other diagonally opposedy slots being open andfacilitating the engagement of a tool with the electrode alignedtherewith and the fulcruming of the tool on the edges of the slot withwhich it is engaged for adjustment of the ground electrodes toward orfrom the insulated electrode.

2. A spark plug including an insulator and an insulated electrodecarried thereby and projecting centrally from its inner end, a tubularmetallic shell for said insulator, the insulated electrode beingsupported centrally of and terminating within the shell, said shellhaving opposed aligned slots extending axially from and opening at itsinner end edge, the plane of the pair of slots being laterally spacedfrom the insulated electrode, and a fiat bendable ground electrodedisposed longitudinally edgewise of the shell in one of the slots andwith its inner end within the shell and spaced from the opposite slotand in side overlapping relation to the insulate-d electrode andlaterally spaced therefrom, said ground electrode having welded jointretaining and grounding connection to the Wall of the slot, said groundelectrode being within the shell and guarded thereby and bendablyadjustable toward or from said insulated electrode, the opposed slotbeing open and facilitating the engagement of a tool with the electrodealigned therewith and the fulcruming of the tool on .the

4 edges of the slot for adjustment of the ground electrode toward orfrom the insulated electrode. 3. A spark plug including an insulator andan insulated electrode carried thereby and projecting centrally from itsinner end, a tubular metallic shell for said insulator, the insulatedelectrode being supported centrally of and terminating within the shell,said shell having opposed aligned slots extending axially from andopening at its inner end edge, the plane of the pair of slots beinglaterally spaced from the insulated electrode, and a ground electrodedisposed in one of the slots and with its inner end within the shell andspaced from the opposite slot and in side overlapping relation to theinsulated electrode and laterally spaced therefrom, said groundelectrode being within the shell and guarded thereby and bendablyadjustable tO- ward or from said insulated electrode, the opposed slotbeing open and facilitating the engagement of a tool with the electrode`aligned therewith and the fulcruming of the tool on the edges of theslot for adjustment of the ground electrode toward or from the insulatedelectrode.

4. A spark plug shell and ground electrode assembly comprising a tubularinsulator shell having opposite pairs of aligned slots opening to andextending axially from its inner edge, the planes of the pairs of slotsbeing transversely spaced and on opposite sides of and in spacedrelation to the axial center of the shell, and bendable groundelectrodes disposed and welded in diagonally opposed slots with theirinner ends free and terminating in spaced relation to the aligned slotsand laterally spaced relative to the center of the shell. f

5. A spark plug shell and ground electrode assemlbly vcomprising atubular insulator shell having an aligned pair of slots opening to yandextending laxially from its inner edge, the plane of the pair of slotsbeing in transversely spaced relation to the axial `center of the shell,and a bendable electrode disposed and fixedly secured in one of theslots with its inner end terminating in spaced relation to the otherslot which is open to receive a tool and permit its engagement witheither side -of the electrode and provide fulcruming support thereforfacilitating the adjustment of the electrode to and from the center ofthe shell.

6. A tubular metallic spark plug shell having an externally threadedportion at its inner end and opposed |pairs of aligned ground electrodereceiving slots in the wall thereof opening to and extending axiallyfrom its inner end edge, the planes of the pairs of slots Ibeingtransversely spaced and on opposite sides of and in spaced relation tothe axial center of the shell whereby ground electrodes may be disposedin diagonally opposed slots and supported with their inner ends inspaced relation to the slot aligned therewith and in laterally spacedrelation to an insulated electrode disposed ycentrally within the shell.

7. A spark plug including an insulator yand an insulated electrodecarried thereby and projecting from its innerl end, a tubular metallicshell for said insulator, the insulated electrode being supportedcentrally of and terminating within the shell, said shell havingangularly spaced electrode receiving slots in the wall thereof extendingaxially from and opening to its inner end edge, and bendable groundelectrodes disposed in the said slots with their inner ends free withinthe shell and in side overlapping relation to the insulated electrodeand laterally spaced therefrom, said ground electrodes being within theshell and guarded thereby. and bendably adjustable towards and from saidinsulated electrode, said shell having tool supporting members angularlyspaced relative to the slots in which the ground electrodes are disposedfacilitating the adjustment of the ground electrodes to or from theinsulated electrode.

8. A spark plug including an insulator and an insulated electrodecarried thereby and projecting from its inner end, a tubular metallicshell for said insulator, the Iinsulated electrode terminating withinthe shell, said shell having angularly spaced slots in the wall thereof,and a bendable ground electrode disposed in one of the slots with itsinner end free and within the shell and in laterally spaced sideoverlapping relation to the insulated electrode and bendably adjustablerelative thereto, the other slot being open facilitating the engagementof -a tool with either side of the free end of the ground electrode andthe fulcruming engagement of the tool with an edge of the slot forladjustment of the ground electrode to or from the insulated electrode.

9. A spark plug shell and ground electrode assembly comprising a tubularinsulator shell having a. slot open to and extending axially from itsinner edge, and a bendable electrode disposed and fixedly secured insaid slot with yits inner end free and spaced from and guarded by thewa11 of the shell and disposed in laterally spaced relation to the axialcenter of the shell, said electrode being mounted within and vprotectedby the shell,

said shell havingr another open slot extending from its inner edge andangularly spaced from and extending from its inner edge, and bendableground electrodes disposed and Welded in said slots with their innerends free and spaced from and guarded by the wall of the shell anddisposed in laterally spaced relation to the axial center of the shell,said shell hav-ing other open slots angularly spaced relative to thepoint of attachment of the ground electrodes to the shell and adapted tofulcrumingly receive a tool engagedwith either side of the free end of aground electrode for adjustment thereofl toward or from the axial centerof the shell.

11. A spark plug shell and ground electrode assembly comprising a,tubular insulator shell having an externally threaded portion at itsinner enda bendable ground electrode disposed within the shell andguarded thereby, and having its outer end fixedly secured thereto withits inner end free and bendable and spaced from and guarded =by the wallof the shell, said shell having an open slot extending axially thereofand into the threads of the shell and angularly spaced relative to thepoint of attachment of the electrode to the shell to facilitate theadjustment of the electrode laterally in either direction by engagementof either side thereof with a tool fulcrumingly engaged with |a sidewall of the slot.

REX J. L. DUVITERER. STEPHEN I. JOHNSON. ANTHONY J. HEIN.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PATENTS Number Name Date 1,940,324 RabezzanaJ Dec. 19,1933 1,943,028 Rabezzana Jan. 9, 1934 2,120,492 Graf June 14, 19382,150,724 Nowosielski Mar.l 14, 1939 2,150,725.. Nowosielski Mar. 14,1939 2,292,974 Smithells Aug. 11, 1942 2,360,279 Rollert Oct. 10, 1944

